Payam Javan: NASA’s Perseverance rover has discovered intriguing rock samples in a dried river channel on Mars that may contain chemical signatures linked to ancient microbial life. The samples, collected from Jezero Crater’s Bright Angel formation, contain organic carbon as well as tiny mineral deposits enriched with iron phosphate and sulfide — compounds that, on Earth, are often produced by microorganisms. Scientists caution, however, that non-biological processes could also explain the findings.

The results, published in Nature, mark the most compelling candidate yet in the rover’s ongoing search for traces of life on Mars, according to lead researcher Joel Hurowitz of Stony Brook University. Perseverance has now gathered 30 rock samples, which NASA hopes to return to Earth for detailed lab analysis. But the sample-return program faces delays, with costs ballooning to $11 billion and timelines slipping into the 2040s. In the meantime, researchers are exploring Earth-based experiments and potential alternatives, such as sending advanced instruments directly to Mars.

Experts not involved in the study praised the discovery as “exciting” while underscoring the need for caution. “We can’t go so far as to say this is proof of life,” Hurowitz noted, but acknowledged that microbial activity remains one possible explanation. NASA leaders, including acting Administrator Sean Duffy, emphasized that all options remain on the table for retrieving or studying the samples, keeping alive the decades-long quest to determine whether Mars once hosted life.